Abstract: The facture behavior of a chromium (Cr) coating/ laser pre-quenched steel substrate system was investigated in this work. The results presented in this work show the crack density of the Cr coating on the laser pre-quenched steel substrate increases with the increase of the thermal fatigue times, and the failure process and modes of the Cr coating / laser pre-quenched steel substrate are the same as those presented in our previous work. However, the crack density of Cr coating on the pre-quenched substrate surface was much lower than that of the Cr coating on the original substrate surface under the same thermal fatigue loading. This indicates the Cr coating on the pre-quenched steel substrate has superior mechanical properties than that on the original steel substrate.

Abstract: The interfacial cracking behaviors of a chromium (Cr) coating/laser pre-quenched steel substrate system and a Cr coating/original steel substrate system under thermal fatigue loading were investigated in this work. The experiment results show that the Cr coating on the pre-quenched substrate surface exhibited a higher resistance of interfacial cracking than that of the Cr coating on the original substrate surface under the same loading condition. This indicates the technology of laser pre-quenching of steel substrate surface prior to plating the Cr coating can improve the interfacial adhesion properties between the coating and substrate.

Abstract: The initial micro-crack density of a chromium coating/steel substrate with and without laser pre-quenching treatment was investigated in this work. It was found the micro-crack density of Cr coating on the pre-quenched substrate surface was much lower than that of the Cr coating on the original substrate surface. Based on the results presented in this work and in the literature, the find presented in this work indicates the lower crack density of the chromium coating on the pre-quenched substrate may improve the mechanical properties of this material system, and it may be an important mechanism responsible for the prolonged lives of workpieces in practice.